Game device, game processing method and information recording medium

ABSTRACT

Smooth, stable and high quality game image is provided by accurately pre-reading background data required for image processing each time. The game device therefore reads background data required for a game that displays a condition of a moving vehicle within a virtual three-dimensional space together with a background in the main memory from a CD-ROM (recording medium) prior to image processing. This device comprises a pre-reading unit for pre-reading background data from a recording medium when reading a start line (reference line) set at a distant position in a specified distance away from the limit line of the visual field direction of display is crossing a new area. A recording medium is a medium that records background data by dividing it into a plurality of areas in advance, and the pre-reading unit comprises a unit for judging on which of the areas the reference line is crossing, and a reading unit for reading in memory the background data of the area judged as being crossed with the reference line.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a video game device, andparticularly relates to a game device capable of expressing morerealistic images in game devices installed at an amusement center orhome and an image processing device used in such game device.

2. Description of the Related Art

Pursuant to the development of computer technology, video game devicesusing computer graphics technology have come into general use. Videogame devices of this kind are widely accepted by the users. A number ofgame devices of various kinds has been devised, and a variety of gamesoftware corresponding to such devices is being supplied.

In order for users to further enjoy video games, it is desirable thatimages with more realistic expressions are displayed on a screen. Invehicle races such as a car race, for example, it is desirable that themovement of vehicles or background is expressed naturally.

As one of the elements to express this natural movement, a data readingcontrol may be proposed in which data of a vast game space is read froma recording medium such as a CD-ROM into the memory inside the gamedevice and thereafter displayed.

Although the same game space, in the case of a game space for games inwhich characters move slowly as in an RPG (Role Playing Game) or amovement of a character to another location is made in an instant, thedata may be read upon temporarily suspending the image processing.Accordingly, such data reading control is very easy.

However, in case of games in which consecutive movement of charactersgives a great deal of influence to the nature of the game, as in a carrace game, etc., background data required to be read together with themovement of the vehicle amount to a huge volume. Accordingly, such datareading control becomes very complicated. For example, if data readingis executed upon temporarily suspending image processing as in the caseof RPG, the game will stop and would not be effective in a car racegame. Reading into a memory all of the background data of the vast gamespace from a CD-ROM, etc. is practically impossible from the perspectiveof memory space and time required for reading.

Accordingly, in case of games which express scenes with charactersmoving at high speed as in conventional car race games, image processingwas executed by dividing background data along travelling route perarea, and pre-reading background data for required areas.

However, a game compatible with this pre-reading method is, for example,a car race game in which a vehicle as a moving object runs apredetermined course (travelling route). A method for this case wassimple, in which background data of the following area was to bememorized in the available memory space upon the vehicle passing acertain point on the course. Some recent car race games or car gamesenable a player to drive the vehicles in any direction within the gamespace. In this kind of game, the travelling directions of a vehicle,which include a plurality of branching running route or areas such as aprairie that is not a part of the original running route, are subject tothe player's operation. In other words, it becomes very difficult forthe device to simply figure out the running route block on which the carmay run in the near future and pre-read background data based on thecurrent speed or location of the vehicle.

Accordingly, the object of the present invention is to provide smooth,stable and high quality game images by accurately pre-reading backgrounddata required for image processing each time, with a simple method, ingames in which a player can move an object such as a vehicle toarbitrary directions within the game space.

SUMMARY OF THE INVENTION

In order to achieve the aforementioned object, the present invention isa game device which makes a work memory read from the storage means,prior to image processing, background data required in games fordisplaying a moving object within a virtual three-dimensional spacetogether with the background, comprising:

-   -   pre-reading means for pre-reading the background data from the        storage means using a reference line set at a distant position        in a specified distance away from the limit line of the visual        field direction of display.

In another embodiment of the present invention, the storage means storesthe background data by previously dividing it into a plurality of areasin advance; and

-   -   the pre-reading means comprises a judging means for judging on        which of the areas the reference line is crossing, and reading        means for storing in the work memory the background data of the        area judged as being crossed with the reference line by this        judging means.

In another embodiment of the present invention, the plurality of areasare respectively stored in the storage means by dividing the content ofbackground data per type and approximately the same size, and the workmemory comprises a plurality of memory blocks set at the same memorycapacity,

-   -   and wherein the reading means is for storing background data of        the respective areas in the memory blocks of more than “n”        blocks (positive integral number) in accordance with the amount        of its data.

In still another embodiment, the reading means includes means forjudging whether the work memory block is a vacant space or not, andmeans for successively storing background data per the area in more than“n” memory blocks when the work memory block is recognized as a vacantspace by this judgment.

In another embodiment, this game device comprises counting means fordetecting whether the moving object exists within the respective areasequivalent to the memory blocks storing background data of the workmemory, or whether an area exists within the visual field, and countingthe moving object or area periodically,

-   -   wherein the reading means includes means for determining the        memory block to store the background data based on the count        value corresponding to each of the memory blocks by the counter        means when it is judged that there is no vacant space in the        memory block.

In still another embodiment, the reading means includes determiningmeans for determining a plurality of consecutive memory blocks whenbackground data to be stored requires a plurality of memory blocks.

In another embodiment, the determining means is for determining theplurality of consecutive memory blocks representing the highest orlowest value by comparing the count values of the plurality ofconsecutive memory blocks.

Furthermore, in another embodiment of the present invention, thedetermining means is for determining the plurality of consecutive memoryblocks representing the highest or lowest value by operating the averagevalues of the count values for the plurality of consecutive memoryblocks. In still another embodiment of this invention, the moving objectis a vehicle that moves within the virtual three-dimensional space.

Another invention to achieve the aforementioned object is a dataprocessing method of a game device which makes a work memory read fromthe storage means, prior to image processing, background data requiredin games for displaying a moving object within a virtualthree-dimensional space together with the background, comprising:

-   -   pre-reading means for pre-reading the background data from the        recording medium using a reference line set at a distant        position in a specified distance away from the limit line of the        visual field direction of display.

Moreover, this invention is also on information recording medium havingrecorded thereon background data and a program for executing therespective means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective diagram showing the outline of the entire gamedevice pertaining to an embodiment of the present invention;

FIG. 2 is a block diagram showing the schematic electrical structure ofthis game device;

FIG. 3 is a diagram showing an example of the landform (background) tobe created in the game space divided into areas;

FIG. 4 is a typical diagram showing an example of the landform mapdivided into area;

FIG. 5 is a diagram typically explaining a part of the memory block tobe set in the main memory as a work memory;

FIG. 6 is a diagram explaining the positional relationship of thereading start line (reference line) and area regarding pre-reading;

FIG. 7 is a flowchart showing the outline of the pre-reading controlprocessing executed by the CPU;

FIG. 8 is a diagram explaining an example of storing data in the memoryblock pursuant to pre-reading; and

FIG. 9 is a diagram explaining another example of storing data in thememory to memory block pursuant to pre-reading.

PREFERRED EMBODIMENTS

The game device pertaining to the embodiments of the present inventionis now explained with reference to FIGS. 1 through 9.

The game device in this embodiment is a car race game for moving avehicle as an object within a virtual three-dimensional space (gamespace). Particularly, provided is a car game that enables a car to runin arbitrary directions when it is difficult to specify the travellingroute to be selected since the route has many branching routes forreaching a destination, or in places such as prairies or villages wheretravelling routes are not clearly prescribed.

This game device is now explained. FIG. 1 is a diagram showing theoutline of the game device pertaining to this embodiment, and FIG. 2 isits electrical hardware block diagram.

As shown in FIG. 1, this game device is structured by mutuallyconnecting a game device body 1, controllers 2 and sub units 3.

The game device body 1 is a control device body for controlling the gameprogress. The game device body 1 can be connected to a plurality ofcontrollers 2 via connectors C. Furthermore, the game device body 1comprises a CD-ROM drive 11, and a removable recording medium (storagemeans) such as a CD-ROM may be installed therein.

The controllers 2 comprise a structure as an operational unit for aplayer to operate, and includes operational buttons 21, cross keys 22,analog direction keys 23 and R trigger switches 24, and can be connectedto a game device body 1 via a connecting cord 4 equipped with aconnector P. These operational units comprise a steering wheel,accelerator, brake, gear shift, etc. required to move a vehicle as anobject within a virtual three-dimensional space. A player properlyoperates those operational units while viewing the monitor screen duringa game. With this, its operational information is conveyed to the CPUinside the game device body 1 described later, and enables a player torun a vehicle in arbitrary directions within the game space under thecontrol of the CPU.

The controllers 2 also comprise backup memory 3, which is removable.

The game device body 1 comprises a structure similar to a computerdevice, and as shown in FIG. 2, comprises a CPU block 30, video block31, sound block 32 and communication device 33, etc.

The CPU block 30 comprises a bus arbiter 300, CPU 301, main memory 302,ROM 303 and CD-ROM drive 11. The bus arbiter 300 is structured to beable to control the transmission/reception of data by allocating busoccupying time to mutually connected devices via bus. The CPU 301 isstructured to be able to access the back up memory 3 via the main memory302, ROM 303, CD-ROM drive 11, video block 31 and sound block 32, andcontrollers 2.

The CPU 301 conducts various processing and controlling required forperforming the game, forwards image data to the graphic memory 311, andcan forward voice data to the sound memory 321. The ROM 303 is a storagearea for an initial program loader. The ROM 303 is an elementstructuring the recording medium, and programs required for processingthe CPU 301 are pre-recorded. As for a recording medium, for example, aCD-ROM may be used.

The CD-ROM drive 11 uses a CD-ROM as a recording medium for dataprovided externally. The main game program, various required data andbackground data (texture data or polygon data) are stored in thisCD-ROM, and those data are read into the main memory 302 when necessary.Other various recording media may be used instead of this CD-ROM.Programs and background data may be forwarded to the main memory via thecommunication device 33. This setting allows transmission of data from afixed disk of a server placed at a remote location.

The Video block 31 comprises a VDP (Video Display Processor) 310,graphic memory 311 and video encoder 312. Through these structures, thevideo block 31 conducts generation of polygon image data (a vehicle asan object), drawing of background image (mapping of texture data),composition of polygon image data as a background image, clippingprocessing, etc. The video encoder 312 is structured to enable theconversion of image data generated by the VDP 310 into specified TVsignals such as NTSC or PAL, and output to the main monitor 35(cathode-ray tube of a TV receiver, etc.) to be connected externally.

The sound block 32 comprises a sound processor 320, sound memory 321 andD/A converter 322. Through these structures, the sound block 32 isstructured to conduct voice synthesis based on wavy pattern data, and toenable the output of sound signals. The D/A converter 322 is structuredto enable the conversion of voice data formed by the sound processor 320into analogue signals, and output to speaker 34 (speaker of TV receiveror speaker of sound device) to be connected externally.

The communication device 33 is, for example, a modem or terminaladapter, structured to enable the access of this game device body 1, andto function as an adapter connecting this game device body 1 with anexternal circuit. The communication device 33 receives data transmittedfrom a server for game supply including an Internet server to beconnected to a public circuit net, and is able to supply such data tothe bus of the CPU block 30. A public circuit net may be a subscriptionline, dedicated line, wire/wireless, etc.

The operation of this embodiment is now explained focusing on readingbackground data into the main memory 302 from the CD-ROM. This readingis executed in a pre-reading method pertaining to this invention underthe control of the CPU 301.

Firstly, the relationship between a landform map as background data tobe set to execute this pre-reading and a memory block with the samememory capacity respectively to be allocated to a fixed area in the mainmemory 302 is explained.

Landform map described in a virtual three-dimensional space availablefor use in a car-race game of this game device is now shown in FIG. 3.The figure shows a xz face of the world coordinate system, and the boldblack line on this map represents the main running route R. This runningroute R comprises a large number of branch routes compared to the onefor a car race game that circulates around an ordinary fixed route.Also, the running route R runs within many kinds and number of fieldssuch as a city, village and prairie, and furthermore, allows to run inarbitrary directions within the field deviating from running the routeR.

A plurality of areas per field type and approximately the same size arenow assumed by dividing the landform map including the running route.With this, areas (AR 1, AR 2, AR 3 . . . . . . ) defined with the thinlines are created. Out of the plurality of areas, as an example, 16adjacent areas (AR, AR2 . . . . . . AR16) are represented as in FIG. 4as the landform map (background data). For example, area AR1 is to bedetermined as a prairie field, and area AR2 is to be determined as avillage field, etc. Considering the difference of data volume (amount ofbackground data) due to objects, etc. arranged in correspondence withthe field type are different, the number of blocks required for thememory area upon writing in the main memory is to be determined asfollows: one block from memory when an area is prairie, two blocks frommemory when an area is village or town and three blocks from memory whenan area is city.

An example of this data writing is shown in FIG. 5. From the top of thefigure, one block is used to store landform data for the prairie area,two consecutive blocks are used to store landform data for the villagearea and three consecutive blocks are used to store landform data forthe city area. Each block MB has the same storage capacity. For thoseblock MB, the count value areas of a software counter CT to be processedby the CPU 301 are set respectively, and its count value is written in.This counter CT periodically judges whether a vehicle exists in arespective area AR equivalent to each block MB within the main memory ornot, or background area-exists within the camera sight or not, and, uponrespective judgments, increments the count value of the counter. CT forthe block MB that stores landform data of that area where no vehicleexists or no vehicle exists within the visual field. Thus, the area ARwith less number of vehicles running has a larger count value of thecounter CT for the corresponding block MB. Accordingly, confirming thiscount value shows the frequency of the vehicle running within itscorresponding area AR. Even if there are a plurality of block MBs whichcorrespond to an area AR, the count value is the same among thoseblocks.

Against the landform data thus divided, the area for pre-reading has tobe found, and method thereof is shown in FIG. 6. It is now assumed thata vehicle VL is running in a village area of area AR 6. For this vehicleVL, along with the travelling direction, a field of view with aspecified angle of visibility θ is set. In a specified distance awayfrom the visual field, a limit line of the visual field LN1, which is tobe a clipping point upon display, is set. Furthermore, within thisvisual field, in a specified distance away from the limit line of thevisual field LN1, a reading start line LN2, which is a part ofpre-reading function of this invention, is set.

This reading start line LN2 is a detector which foregoes to determine anarea to start pre-reading landform data. The adopted method is that,when each area is expressed with its circumcircle, this line LN2specifies in which circumcircle (area) line LN2 within the sight is tobe crossed (or entered), and to determine the area with the specifiedcircumcircle as a targeted pre-reading area. In case of FIG. 6, it maybe judged that current the pre-reading areas are both AR 10 and AR 11since the reading start line LN2 is crossed in both circumcircles ofcity area AR 10 and its adjacent village area AR 11.

Based on this pre-reading method, an example of reading processing forlandform data (background data) to be executed with the CPU 301 is nowexplained according to FIG. 7. This processing is executed, for example,with a timer interruption method for each fixed time.

The CPU 301, at first, reads operational information by a player (stepS1), and specifies the current location of the vehicle and theproceeding direction on the xz face of the world coordinate system (stepS2).

Next, upon looking at a visual field along with the travelling directionfrom the current location of the vehicle (viewpoint), the CPU 301 judgeswhether reading the start range, i.e. reading start line LN2, entersinto any new area AR (yet to read background data) in a method using thecircumcircle of area as stated above (step S3). When this judgment is“no,” processing will be returned to the main routine since the readingstart line LN2 has not crossed a new area AR yet.

On the other hand, when the judgment is “yes” at step S3; i.e. readingstart line LN2 crosses one or more new area ARs, the CPU 301 judgeswhether there are any required number of consecutive memory block MBsunused in the main memory 302 (step S4). However, in case the number ofrequired memory blocks to store background data is one, “required numberof consecutive memory block” means one memory block. When a judgment atthis step S4 is “yes,” background data (landform data) is to be readfrom a new area AR, and written in the vacant memory block.

On the other hand, when the judgment is “no” at step S, i.e. there areno required number of consecutive memory blocks unused, the CPU 301judges whether, in case of a city, for example, there are requirednumber of memory blocks which stores background data consecutively forone city area in used memory blocks MB, . . . . . . . . . (step S6).When this judgment is “yes,” background data for a new area AR is to bestored in the memory block which represents the largest value (step S7)by comparing the count values corresponding to the memory block MB. Itcan be assumed that a large count value suggests that the frequency ofusage for the background data of the memory block was low in the past,and will be the same in the future as well. According, background dataof such memory block takes priority to be renewed.

On the other hand, when the judgment is “no” at step S6, search is madefor memory blocks that store background data consecutively over areaswith a plurality of types, and more than one set of required number ofblocks is assured by combining them (step S8). Next, for each set of theconsecutive memory blocks, the average count value of the respectivememory blocks is computed (step S9). Furthermore, the CPU 301 comparescomputed count values, judges a set of memory blocks with the largestcount value, and stores in the memory background data of the new area ARfor the respective memory blocks of the set (step S10). The reason forsearching a set of memory blocks with the largest count value is thesame as the above.

The examples of the above stated pre-reading processing are shown inFIG. 8 and FIG. 9 as a typical diagram. In those diagrams, singlecircles indicate the blocks storing background data (landform data) readin the past, and double circles indicate blocks storing background datafor areas with a vehicle, or blocks storing background data for areaswithin the sight of the area. “*” indicates that the block storesbackground data of one area consecutively (connecting with “−”).Furthermore, “+” indicates unused blocks.

The example in FIG. 8 indicates the process of storing background dataof a new area AR by using an unused (vacant) memory block MB in the mainmemory 302 (see step S3-S5 in FIG. 7). It is assumed that the vehicleshave already moved into the new area.

The example of FIG. 9 indicates a renewing process of the memory blockMB with background data stored in the past by new background data. Inother words, this indicates that, after detecting a new area andrenewing the past consecutive background data with the new backgrounddata, vehicles have already moved into this new area. Especially, theexample of FIG. 9 explains the condition that requires four consecutivememory blocks as places to secure the background data of the new area.Accordingly, the average count value was operated through the processingof steps S3, S4, S6 and S8 through S10 in FIG. 7, and memory block Nos.6 through 9 were selected. In this case, an adjacent memory block No. 10is handled as a vacant block. In this example, background data readlater (for example, background data of block Nos. 6 through 10) isdeleted earlier than those read previously (for example, background dataof block Nos. 1 through 5). This is because the running course ofvehicle is not linear, but, in many cases, so-called “meandering” or“zigzag” running, in which vehicles directly enter into the area read inthe past from another course.

Pre-reading of background data (landform data) together with operationalinformation enables the CPU 301 to control and instruct image processingof a car race game. In this pre-reading processing, the pre-readingstart line is set in the further specified distance ahead of sightlimiting line, and the vehicle proceeding area is accurately detected sothat sure and stable area detection, i.e. pre-reading can be conducted,which is different from conducting pre-reading unreasonably.Accordingly, it is neither necessary to particularly increase thestorage capacity of the main memory in the device, nor to readbackground data by stopping the image processing. Thus, on the screendisplayed on the monitor 35 by image processing using this backgrounddata, displayed is an image of a vehicle running which is stable havinghigh quality without any missing image, etc.

In the above stated embodiments, it was explained that the pre-readingstart line for pre-reading detection is linear. However, this may be acircular arc form against the view point. A judgment whether thispre-reading start line crosses a new area or not may be made bycomparing the square area itself and the location of the pre-readingstart line, not by setting the area's circumcircle.

Furthermore, regarding the handling of count values of the counter whichdisplays the usage frequency of background data in the memory block,contrary to the above, it may be possible to decrement a count valuefrom the specified value after detecting that no vehicle exists in thecorresponding area for each fixed time. It may be also possible to setthe range of count value within a specified range in the main memoryrelating to each block MB, not within the block MB.

According to the game that allows a player to move an object such as avehicle in arbitrary directions within the game space pertaining to thepresent invention as stated above, though a relatively easy method, itis possible to provide a smooth, stable and high quality game image byaccurately pre-reading background data required for image processingeach time.

I claim:
 1. A game device that reads from comprising a game executingmeans, an image processing means, a work memory, a control means for aplayer to enter control instructions, and a mounting means to which astorage means is detachably mounted, prior to image processing,backgroundwherein the storage means stores a game program that respondsto control instructions from the player that are executed on the gamedevice to move a moving object in an arbitrary direction on a terrainthat includes a predetermined racing road and areas off thepredetermined racing road, the terrain comprising a plurality ofbranching routes for reaching a destination in which a route to thedestination is not specified and the moving object is moved in anunrestricted route on the terrain in response to the controlinstructions to reach the destination, and the storage means storesterrain data required in games for displaying a the moving object withina virtual three-dimensional space together with a background,comprising: the terrain by dividing the terrain into a plurality ofareas selectable in accordance with a heading direction of the movingobject, pre-reading means for pre-reading said background data from saidstorage means by establishing an area for pre-reading whichincludes:wherein the game device executes the game program, in responseto manipulation by the player of the control means, to performoperations of: (a) determining a current position and current headingdirection of the moving object on one of the plurality of areas on whichthe moving object is currently located; (b) setting a predeterminedangle-of-visibility based on a view angle viewed from a viewpoint, whichis set at the current position of the moving object, toward the currentheading direction of the moving object, the current heading directionbeing selected on one of the plurality of areas by the player; (c)setting a limit-line of a visual field, beyond which a scene of theterrain viewable from the viewpoint is omitted from being displayed, ata predetermined distance towards a front of the visual field, and awayfrom the viewpoint within the view angle ahead in the current headingdirection; (d) setting a pre-reading start line at a predetermineddistance beyond a front of away from the limit-line of the visual fieldthat moves within the view angle further ahead in the current headingdirection of the moving object when viewed from the moving object,wherein said storage means stores said background data by dividing saidbackground data into a plurality of areas in advance; said pre-readingmeans comprising judging means for judging which of said(e) determininga specific one of the plurality of areas saidwhich crosses thepre-reading start line is crossing to determine a specific area fromamong the plurality of areas, and; reading means for reading(f)pre-reading the backgroundterrain data ofcorresponding to the determinedspecific area judged as being crossed with said pre-reading start lineby the judging means, wherein said plurality of areas are respectivelystored in saidfrom the storage means by dividing the content ofbackground data per type; said game device further comprising ainto amemory space of the work memory; including a plurality of memory blockseach set at a same memory capacity, wherein said reading means includesmeans for storing the background data of the crossed area in an integralnumber “n” of said memory blocks in said work memory in accordance withthe amount of the background data to be stored, and wherein said readingmeans includes means for judging whether one or more of said memoryblocks of said work memory are a vacant space or not, and means forsuccessively storing the background data of said crossed area in saidintegral number “n” of said memory blocks when said integral number ofsaid memory blocks are judged as vacant space and of sufficient capacityto store the background data; said game device further comprisingcounting means for detecting whether said moving object exists withinsaid areas corresponding to memory blocks storing background data, or anarea that exists within the visual field, in said work memory, andcounting said moving object or visual field area (g) if, as the movingobject moves, the limit line moves on the determined specific area, thendisplaying the terrain corresponding to the determined specific areabased on the data read into the work memory in operation (f); and (h)executing operations (a) to (g) periodically, wherein said reading meansincludes means for determining the memory block to store said backgrounddata based on a count value determined for each of said memory blocks bysaid counting means when it is judged that there is no vacant space insaid work memory in accordance with changes of the current location andthe current heading direction of the moving object on the terrain inresponse to manipulation by the player of the control means.
 2. A Thegame device according to claim 1 9, wherein said reading means includesdetermining means for determining a plurality of consecutive memoryblocks are used when background the terrain data to be stored requires aplurality of memory blocks.
 3. A The game device according to claim 110, wherein said determining means is for determining a plurality ofconsecutive memory blocks representing a highest or lowest value bycomparing said count values of said plurality of consecutive memoryblocks are selected for storing the terrain data.
 4. A The game deviceaccording to claim 1 9, wherein said determining means is fordetermining a plurality of consecutive memory blocks representing ahighest or lowest value are determined by computing average values forsaid plurality of consecutive memory blocks.
 5. A The game deviceaccording to claim 1, wherein said the moving object is a vehicle thatmoves within said the virtual three-dimensional space.
 6. A The gamedevice according to claim 1, wherein said background the moving objectis a vehicle and the terrain data is landform data prepared to enable athe vehicle to travel in arbitrary directions on land represented by thebackground terrain data.
 7. An A non-transitory computer-readableinformation recording medium having recorded therein said background theterrain data and programs the game program for executing the respectivemeans according to operations specified in claim
 1. 8. A data processingmethod for a game computer device, comprising: a data processing means,a work memory, a control means for a player to enter controlinstructions, and a mounting means to which a recording medium isdetachably mounted, reading background data required for a game thatdisplays a moving object within virtual three-dimensional space togetherwith a background in working memory from memorizing means prior to imageprocessing, wherein said background data is pre-read from a recordingmedium by establishing an area for pre-reading which includes:whereinthe recording medium stores a game program that responds to controlinstructions from the player that are executed on the computer device tomove a moving object in an arbitrary direction on a terrain, and therecording medium further stores data for the terrain by dividing theterrain into a plurality of areas selectable in accordance with aheading direction of the moving object, the method comprising: (a)determining a current position and current heading direction of themoving object on one of the plurality of areas on which the movingobject is currently located, wherein the terrain on which the movingobject is currently located includes a predetermined racing road andareas off the predetermined racing road, the terrain comprising aplurality of branching routes for reaching a destination in which aroute to the destination is not specified and the moving object is movedin an unrestricted route on the terrain in response to the controlinstructions to reach the destination; (b) setting a predeterminedangle-of-visibility based on a view angle viewed from a viewpoint, whichis set at the current position of the moving object, toward the currentheading direction of the moving object, ; (c) setting a limit-line of avisual field, beyond which a scene of the terrain viewable from theviewpoint is omitted from being displayed, at a predetermined distancetowards a front of the visual field, andaway from the viewpoint withinthe view angle ahead in the current heading direction; (d) setting apre-reading start line at a predetermined distance beyond a front ofaway from the limit-line of the visual field that moves within the viewangle further ahead in the current heading direction of the movingobject when viewed from the moving object; said recording medium storingsaid background data by dividing said background data into a pluralityof areas in advance, said plurality of areas being respectively storedin said recording medium by dividing the content of background data pertype and approximately the same size; judging(e) determining a specificone of the plurality of areas which of said areascrosses saidpre-reading start line is crossing to determine a specific area fromamong the plurality of areas, and; (f) reading the background terraindata of corresponding to the determined specific area judged as beingcrossed with said pre-reading start line from the recording medium intoa memory space of the work memory; (g) if, as the moving object furthermoves, the limit line moves on the determined specific area, thendisplaying a scene of the terrain corresponding to the determinedspecific area based on the data read into the work memory in (f); andstoring background data of the crossed area in an integral number “n” ofmemory blocks in said working memory in accordance with an amount of thebackground data to be stored, said working memory including a pluralityof memory blocks each set at a same memory capacity; judging whether oneor more memory blocks of said working memory are a vacant space or not,and successively storing the background data of said crossed area insaid integral number “n” of said memory blocks judged as vacant spaceand of sufficient capacity to store the background data; detectingwhether said moving object exists within any of said plurality of areascorresponding to memory blocks storing background data, or an area thatexists within the visual field, in said working memory, and countingsaid moving object or area (h) executing (a) to (g) periodically; anddetermining the memory block to store said read background data based ona count value determined for each of said memory blocks by said countingwhen it is judged that there is no vacant space in said working memoryin accordance with changes of the current position and the currentheading direction of the moving object.
 9. The game device according toclaim 1, wherein the work memory is defined to include a plurality ofmemory blocks set at a same memory capacity and step (f) comprises:storing the terrain data corresponding to the specific area in anintegral number “n” of the memory blocks in the work memory inaccordance with an amount of the terrain data to be stored; judgingwhether or not one or more of the memory blocks of the work memory are avacant space, and successively storing the terrain data corresponding tothe specific area in the integral number “n” of the memory blocks whenthe integral number “n” of the memory blocks are judged as vacant spaceand of sufficient capacity to store the terrain data.
 10. The gamedevice according to claim 1, wherein the work memory is defined toinclude a plurality of memory blocks each set at a same memory capacityand the game device further comprises a counting means and performssteps of: periodically counting a frequency when pre-read data has beenused for displaying the terrain with respect to the memory blocks; andselecting one of the memory blocks based on the counted frequency, forstoring terrain data when it is judged that there is no vacant space inthe work memory.
 11. A game device comprising a game executing means, animage processing means, a work memory, a control means for a player toenter control instructions, and a mounting means to which a storagemeans is detachably mounted, wherein the storage means stores a gameprogram that is executed by the game device and responds to controlinstructions from a player that are executed on the game device to movean object indicative of a car vehicle in an arbitrary direction on aterrain that includes a predetermined racing road and areas off thepredetermined racing road, the terrain comprising a plurality ofbranching routes for reaching a destination in which a route to thedestination is not specified and the object is moved in an unrestrictedroute on the terrain in response to the control instructions to reachthe destination, and the storage medium further stores data for theterrain by dividing a plurality of areas selectable in accordance with aheading direction of the object, wherein the image processing meansdisplays a scene of the terrain from a view angle viewed from aviewpoint, which is set at a current location of the object, in concertwith a heading direction of the object in response to manipulation bythe player of the control means, wherein the game device executes thegame program in response to manipulation by the player of the controlmeans, to perform operations of: (a) determining a current position andcurrent heading direction of the object on one of the plurality of areason which the object is currently located; (b) setting the view angleviewed from the viewpoint toward the current heading direction of theobject, the current heading direction being selected by the playerbetween the current position and the destination; (c) setting alimit-line, beyond which the scene of the terrain viewable from theviewpoint is omitted from being displayed, at a distance away from theviewpoint within the view angle ahead in the current heading direction;(d) setting a reference line at a certain distance away from thelimit-line further ahead in the current heading direction; (e)determining a specific one of the plurality of areas, which includes thereference line within the view angle viewed from the viewpoint at whichthe object is currently positioned among the plurality of areas of theterrain; (f) pre-reading the terrain data corresponding to thedetermined specific area from the storage means into a memory space ofthe work memory before the limit-line reaches the specific area; (g) if,as the object further moves, the limit line moves on the specific area,then displaying a scene of the terrain corresponding to the determinedspecific area based on the terrain data which was already read into thework memory at operation (f); and (h) executing operations (a) to (g)repeatedly in accordance with changes of the current position and thecurrent heading direction of the object in response to manipulation bythe player of the control means.
 12. A non-transitory computer-readablestorage medium storing a game program and data readable by a computer,wherein the game program is executed by the computer in response tocontrol instructions of a player that are executed by the computer tomove an object in an arbitrary direction on a terrain that includes apredetermined racing road and areas off the predetermined racing road,the terrain comprising a plurality of branching routes for reaching adestination in which a route to the destination is not specified and theobject is moved in an unrestricted route on the terrain in response tothe control instructions to reach the destination, and the storagemedium further stores data for the terrain by dividing a plurality ofareas selectable in accordance with a heading direction of the object,and the game program is executed by the computer in response tomanipulation by the player to performs operations of: (a) determining acurrent position and current heading direction of the object on one ofthe plurality of areas on which the object is currently located; (b)setting a view angle viewed from a viewpoint, which is set at thecurrent position of the object, toward the current heading direction ofthe object; (c) setting a limit-line, beyond which a scene of theterrain viewable from the viewpoint is omitted from being displayed, ata distance away from the viewpoint within the view angle ahead in thecurrent heading direction; (d) setting a reference line at a certaindistance away from the limit-line further ahead in the current headingdirection; (e) determining a specific area, which includes the referenceline, among the plurality of areas of the terrain; (f) reading the datacorresponding to the determined specific area from the storage meansinto a memory space of the work memory before the limit-line reaches thespecific area; (g) if, as the object further moves, the limit line moveson the determined specific area, then displaying a scene of the terraincorresponding to the determined specific area based on the data readinto the work memory at operation (f); and (h) executing operations (a)to (g) repeatedly in accordance with changes of the current position andthe current heading direction of the object.
 13. The storage medium ofclaim 12, wherein: the object is indicative of a car vehicle, and datafor the terrain is stored by dividing the terrain into areas of a town,a city, a village, and a prairie.